The third season of my hypothetical Pretty in Pink TV show would take place from Fall 1985 through Summer 1986. The only John Hughes teen movie to come out during that time period was Pretty in Pink itself, but that's plenty. Especially considering that we took the name of the series from it, but that does raise an issue with naming the season. Instead of naming it after one of the movies whose events it covers (like we've been doing), I'm calling it "Isn't She...?" after an iconic lyric in the Psychedelic Furs song that gave the film its name.
We don't have any new freshmen characters this season. From here out, we'll stick with the characters we have. Breakfast Clubbers John, Claire, and Andrew all graduated at the end of last season, so some of this season will focus on the remaining two: Brian and Allison. Allison's friendships with Andy and Claire last year had a big impact on her. She never became one of the snobby rich kids, but that group accepted her because Andy was dating her. They didn't fully understand it, but they didn't pick on her, either.
Things are hard with Andy as a freshman in college, but he was accepted to University of Illinois at Chicago, so at least he's still local and they're trying to make it work.
Brian's a different story though. He didn't get picked on as much with Claire, Andy, and Bender watching out for him, but he also never escaped being labeled as a nerd and was always sort of an outsider to the rest of the Club. He's still hanging out with younger students like Farmer Ted and Gary and Wyatt.
Ferris and Cameron have more or less split from the rest of the nerd clique. They both come from wealthy families, so now that they're upperclassmen, the student population is starting to give them more respect. There's no dramatic split from the other nerds; in fact, Ferris is especially gracious and cool with them. It's just that he (and by extension, Cameron's) social circle is expanding. That puts Ferris in contact with Sloane and at some point in the season, they start dating. We'll also focus a lot on Cameron's home life: his increasingly shaky relationship with his emotionally distant father and his mother's inability to intervene.
Switching over to Andie Walsh, the first half of the season has her starting to get tired of Duckie, so she begins hanging out at an 18-and-older club where he can't get in. She also gets an after-school job at the record store TRAX. The big focus though - especially in the second half of the season - is on Blane's asking Andie to the prom. There's fall out with Blane's friends; there's fall out with Duckie. It's a whole big mess.